A surface of area S is placed perpendicular to the direction of travel of a plane wave. The energy per unit time intercepted by the surface is E when the amplitude of the wave is A. The area of the surface is reduced to `1/2` S and the amplitude of the wave is increased to 2A. What is the energy per unit time intercepted by this smaller surface?
| A. |
4E |
| B. |
2E |
 |
| C. |
E |
| D. |
`1/2E` |